Alarm system



J. C. FIELD ALARM SYSTEM Aug. 8, 1933.

Filed Jan. 28, I931 INVENTOR By c. FIELD J imdd ATTORNEY Patented Aug- 1 new This invention relates to alarm systems and more particularly to burglar alarm systems for protecting vaults and the like by means of a carbon button transmitter mounted on thewall thereof. 7 I a An object of the present invention is to pro- 7 vide a burglar alarm systemfor vaults and the stable condition. 1

like which'will be simple in construction; cheap to manufacture and maintain and yet'be very efficient in operation.

Another objectoftheinvention are provide a burglar alarmsystem which depends upon a carbon granule transmitter button for operation g the button in a with means for maintainin A further object is to provide'means for-allowing certain changes in current which are caused by the button itself to have no efiect on the circuit while changes in the current caused byoutside influences cause the alarm to operate; In'the present type of burglar alarm systems employing a carbon granule transmitter button for detecting the vibrations imparted to 'the structure to be protected, it has been'iound that a number of' false operations have been ex perienced due, to the breathing of the button increasing or decreasing the current throughthe galvanometer sufiicient to "close its low or high contacts.

i In accordance with the presentinvention the applicant has "not only prevented the breathing of the button fromaffecting the circuit but has also eliminated the galvanometer and voice fre quency relay which. heretofore (were considered indispensable and essential parts of the circuit. In the above system forming the subject matter of this application, the applicant has not .only eliminated anumber of pieces of expensive ap-, paratus but has devised 'a circuit which dependson the change in D. C. resistance of the button when agitated to reducethe current in one winding of the polar relay sufficiently for .a second and opposing winding to operate the relay.

provided means in the circuit for keeping the,

button in astableicondition and responding only tdvibrations imparted to the Wall, thereby eliminatinga chance of false operation due to the breathing action of the button. r

In the' drawing which discloses a. complet system including "a" central office and a substation, at which there is a vault to beprotected, A- indicates a vault protector system located at the premises to be protected and B 'a 'c'entral office system at which signals are received from the protected premises; a a. a a 1 The system'at A is connected-to the system at B over the line wiresl and 2,-current-being supplied to'the' line by battery} located at the In addition to this the-applicant has" central oiiice. Connection is established between the central office and'the line wires 1 and 2 leading to the protected'premises'by means of a key i.

Tl i'enorma l circuit-existing between the protected premises-A and the central office B may be traced as follows; negative terminal of cen-' tral-ofiice battery 3 atthe central ofice B, con ductor il, winding of relay 31; winding -'c f re "lay 30,- energizing coil25 of galvanomete 24,

upper inner contact 42 of key 4, upper outer spring contact 69, line Wire 2, winding of changrric enrelayjLl;conductor '43, armature 39 of relay 7 8; contact "conductor 7l,- brush 56f'segn1ent 57, conductor"65; resistance'fifi, resistance 63,

conductor 72, ringer 19, line wirel, lower outer springjcontact 73 of key}; lower inner contact 45' to th'e positive terminalof central ofiice batt 1 1-1 v. Located at the protected premises is a micr'ophone S-Whichmay-be foriiistance, an inertia type microphone such as is disclosed in C. R.

Moore Patent -l; i26,"l57 The microphone 5 is energized by alocalbattery ii-andgoverns the" operationof a difierential relay "7. The difierential relay '7 controls the operation of a relay 8 Whiohoperats to connect the conductors 43' and 44 leading to the line wires-1 and 2 and cause an alarm tobegiven" at the central of fiCelB. I. ,,I 1, A

In series with the microphone '5 and left-hand winding of thedifrere'ntial relay '7 is a lamp 9 and a relay 10. The left-hand winding of the differential relay 7 has a greater number of turns than the righthandwinding and normally pulls the armature ll against contact 12' against the actiono'f a retracting spring-l3 and the counter-- minal o flocal battery 6, conductor 32, microphone 5, conductor 33, lamp 9, relay l0,'conductor 34 to the left-hand windingof-difierential relay-7, conductor 35, front contact 12 of differential relay '7, armature 11; conductor 36, conductor '79, conductor 88 to the'positive pole of local battery 6. v

' When vibrations'are imparted to the microphone 5 throughthe walls of'the protected structure such as would be caused bya hammer blow or the like, the D'. C. resistance'in the microphone 5 is increased to such an extent as to cause a sufficient weakening in the pull of the left-hand winding of the'difi'erential relay 7 for it tobe overcome by the pull of the right-hand winding and the pull of the retracting spring 13. The armature 11' is brought over against the back contact 1a and brings into circuit connection with the local battery 6 the relay 8 which operates to connect the conductors 43 and 44; The connecting of the conductors 43 and 44 completes a new circuit to the galvanometer 24 located at the central office B. The galvanometer 24 has an energizing coil 25, low and high contacts 26, a calibrated scale 27 and a movable pointer contact 28.

The galvanometer 24 is normally maintained in a balanced'condition with the movable pointer contact 28 maintained by its energizing coil '25 in a midway position between its low and high contacts 26-26. Current is supplied to the galvanometer 24 to normally maintain it in this balanced condition by the central office battery 3.

When the relay 8 is brought into operation by the operation of the differential relay 7 and conductors 43 and 44 are connected, the normal circuit including the brush 56 and segment 57 of the changer relay 21 is opened. and the new circuit to the galvanometer 24 is completed through armature 39 and front contact 40 of relay 8 and over conductor 44 and conductor 72 to ringer 19 and line wire 1. The increase in current in changer relay 21 causes this relay to pull up armature 91 against contact 90. 7

The new circuit completed to the galvanometer 24 by connection of the conductors 43 and 44 may be traced as follows: negative terminal of the central ofiice battery 3, conductor 41,

winding of relay 31, winding, of, relay 30, coil 25 against contact 90-by changer relay 21. tact. 90 is" connected to conductor 43 by-conducoi the galvanome'ter 24, upper inner contact 42 of key 4,-1 upper outer spring contact 69, line Wire 2, winding of changer relay 21, conductor 43, armature 39 of relay 8, front contact 40, conductor 44, conductor '72, ringer 19, line wire 1,

lower outer spring contact 73 of 'key 4, lowerinner contact45 to: the positive terminal of the central ifiice battery 3. This new circuit to: the

galvanometerisalso made doubly sure of completion through the-pulling up of armature 91 Contor 89'. Armature 91 isconnectedto conductor 72 by conductor 92. When this new circuit is completed to the galvanometer 24 the movable pointer contact 28 is moved into engagement with one of 'the.contacts 26 which brings into circuit connection with the central ofiice battery 3 a drop signal 23 which is operated to advise an attendant at the central office B of disturbances occurring in the microphone 5 at the protected premises. The circuit for the drop .signal 23 may be traced as follows: negative terminal of the grounded central oflicebattery 3, conductor 48, conductor 49, movable pointer contact 28 of galvanometer 24, contact 26, conductor 85, winding of drop signal relay 23- to ground.-

To. make doubly sure of the operation of the drop signal 23 even if incomplete contact is made between the movable pointer 28 and con ing of relay '23 to ground.

The lamp9 at the-protected premises is placed series with: the microphone 5 and; the lefthand winding of the differential relay 7 to prevent gradual changes of current caused by breathing of the microphone 5 from causing operation 'of the differential relay 7 and the consequent operation of relay 8 and the operation of the drop signal 23 at the central office B. The filament of the lamp 9 may be of tungsten or any other material, the resistance of which increases with current. Slight and comparatively slow changes in resistance in the microphone 5 caused by its breathing action will have no appreciable effect upon the pull of the lefthand winding of difierential relay 7 by reason of the corresponding opposite change in resistance of the lamp 9. Changes in resistance in the microphone 5 (carbon) caused by its breathing action are comparatively slow and any gradual decrease in the resistance of the microphone 5 and the consequent increase in the flow of current through the conductor 33 will be resisted by the lamp 9, the resistance of the filament of which slowly increases with increase in 'current' Likewise any gradual slight increase in resistance of the microphone 5 caused by its breathing action and the consequent gradual decrease in current flowing through the conductor 33 will be prevented from appreciably affecting the pull of the left-hand winding of differential relay 7 because of the time lag in change of resistance in the filament of the lamp 9.

Any sudden and comparatively great increase in resistance in the microphone 5 such as would result from a hammer blow on the wall of the protected structure and the consequent suddenlesseningto an appreciable degree of the amount of current flowing in the conductor '33 will result ina sufficient weakening of the pull of the left-hand winding of differential relay 7 to allow the pull of the right-hand winding and the pull of the retracting spring 13 to overcome it and bring. the armaturelI over against contact 14 and complete the circuit to relay 8 which upon pulling up its armature 39 against contact 40' will close the circuit" to galvan'ometer 24' at the central office B over conductor 44 and result in the display of a signal at the central office B as abovefdescribed'. I

The relay I0 is not operated normally by the normal current passing through the micro-- phone 5 but will operate to" connect the conductors 43 and 44' and close the circuit to the alvanometer 24 at the'centra'l office B and cause the display of a signal thereat should the microphone 5 be short-circ'uited or an exceptionally strong current applied thereto.

In the event of a break occurring in the systemat the protected premises, suchas Would'- be caused by disconnection of the local battery 6; or any opening in the circuit of the local battery 6, relay 15 which is normally operated to pull up'its armature 16 will release its armature and cause a connectionbetween the conductors 43' and 44 which will close the circuit to the galvanometer 24' of the central ofiice B and will result in the display of a signal thereat.

When the differential relay 7 is operated to allow armature 11 tobe moved over against the back contact 14 tocause the operation of relay 8 and the operation of a signal at the central office B, the circuit of the normally operated relay 15 is opened and armature 16 moves over against the contact 55 and connects conductors 43v and 44. This makes doubly sure the connection of conductors 43 and 44- when differential relay 7 islbrought into operation by action of the microphone 5. Inthe event of there being incomplete connection between armature39 and front contact. 40 of relay 6, the new circuit of the galvanometer What the central oifice B will be completed by armature 16. and contact 55 of the normally operated relay 15. It 1 will be seen therefore that thereis provided in this systeminsurance against inoperation, due. to

dirty or oxidized contacts; For instance if incomplete contact is made between armature 16 and contact 55 of relay 15, theqcircuit to the galvanometer 24131113118,CSII GISJDfi'lCB B is com.- pleted by connection'between the armature 39 and front contact 40 of relay 6, and, vice versa, if thereshculd be incomplete connection between the armature 39 and the front contact 40 of relay 8, the circuit to the galvanometer 24 at the central of ce B is completed ,bythe connection of armature 16 and contact 55 of relay The normal circuit through relay 15 may be traced as follows: negative terminalwof local battery 6, conductor 32, conductor 82, contact 81, resistance element rsll, conductor 83; armature is, contact 8 Winding of relay 15, right-, hand winding of differentialrelay 7, contact 12, armature '11, conductor 36,, conductor. 79, condu'ctor 88ito the positive terminal of local battery6. v

The relay 8 has two left-handarmatures 17 andlS which pull up when the relayoperates.

The extreme left-hand armature 13 when pulled up opens the circuitthrough the winding of relay 15 and the right-handwinding of diiTerential relayfil, and makes this right-hand winding inactive. The rendering inactive .cf the righthand winding jOf differential relay 7 by opening of the circuit 'at armature 18 of relay 8, {allows the'left-hand winding of differential jrelay 7 to pull the armature ll over ,against contact 12, and makes positive the restoration to normal of the differential relay 7/ When relay. 8 is operatedto pull up its' a rmature 18 and open the circuit otthe right-hand winding of differential relay '7, it also pulls up armature 1'7 against contact 86 and completes the circuit of the left-hand winding of ,difierentialrelay 7. This circuit may be traced as follows: negative terminal. of local battery 6, conductor 32, microphone 5, conductor 33, lamp 9, winding of relay 16, conductor .34, left-hand winding of differa ential relay '7, conductor 8'7, contact 86, armature 17 conductor 83, to the positive terminal of local battery 6. a 1

For testing purposes a buzzer 20 is located in close proximity to'the microphone 5 at the protected premises. This, buzzer 20-may be operated from the central station B to set up vibrations in the walls of the protected structure and and to make tests of the condition of the system,

the changer relay 21 isprovided with a pivoted arm 93 which 'by meansjof a pawl i le-rotates a brush 56' over a set of contact segments 57-57, 5858 and 59'59. Segments 5'757 are con- -nected to conductor '72 through conductor 65, resistance 66 and resistance 63. Segments 5858 are connected to conductor 72 through conductor 62 and resistance 63. Segments 59-59 H are in electrical connection with buzzer relay 61 over conductor 60.

resistance 66 is shorted out.

The changer: relay 21 will not. operate to pull up pivoted .arm 93- and cause rotation of the brush 56 over the segments 5757, 58-58 and 5959 by current supplied by the central ofiice battery 3, but will operate to pull uppivoted arm 93and move the brush 56 the space of one segment'each time a high potential battery 22 is brought into circuit connection by operation of the key 4; When the brush 56 is on either of the. segments 57-57 it isin series connection with the resistance elements 66 and 63 and conductor '72. When the brush 56is on either of the "segments 58-58 it is in series connection with resistance 63 and conductor 72 and the- When the brush 56 is on either of the segments 59-59 both of the resistances 66. and 63 are shorted out and the brush 56 is electrically connected to buzzer relay Glover conductor 60. i I The normal circuit is'as, previously described with the brush 56-engaging one of the segments 5'15'7 and with both resistance elements 66 and 63 included in the circuit. Under this condition the movable contact member 28 of galvanometer 24 is in its central position. as shown midway between'the fixed contacts 26-.26.-

By operating key 4 and bringing into the circuit the high potential battery 22 the changer relay 21 will operatev to move pivoted arm 93 and the .pawl 94 to move the brush 56 around to the next segmentwhich is. 58. This will cause shorting out of the resistance 66. When'the key 4-. is released and the central office battery 3 is again .brought into-the circuit, the increasein current in the circuit due to the removal therefrom of the resistance66 will result in a slight deflection ofthemovablepointer contact 28 of the galvanometer 24. The normal circuit for operation of the changer relay 21 may be traced as follows: grounded high potential battery 22, resistance 67, contact 68, upper outer spring cont act'69 of key-4, line wire 2, winding of changer relay 21, conductor 43, armature 39 of relay 8, back contact 70, conductor 71, brush 56, segment 5'7, conductor 65, resistance 66, resistance 63, conductor 72, ringer 19, line wire 1, lower outer spring contactv 73 of key 4, contact 74. to ground. By again operating key 4 the changer relay 21 willcause movement of the pivoted arm 93 andpawl94 and the rotation of the brush 56 to the next segment which is 59. When the brush 56 is moved to segment 59 both resistance 66 and resistance 63 are shorted out and buzzer relay 61 which is connected to segment 59v by conductor 60 and to conductor '72 bycoriductor 64 is brought into the circuit-and caused to 0p erate to pull up armature against contact '76 and close the circuit to the buzzer 20' from the local battery 6. 7 When the key .4 is released and the central ofiice battery :3 is againbrought into circuitftne increased current therein resulting from the removal from the circuit of the resistance elements 66 and 63 results in astill further deflection of the movable pointer contact -'28 of the galvanometer 2 4. The circuit now established maybe "traced as follows: negative terminal of centraloffice battery 3, conductor 41, winding of relay 31, winding of, relay 30, energizing coil 25 0f galvanometer 24, upper inner contact 42' of key 4, upper outer spring contact 69, line wire 2, winding of changer.relay,2l, conductor 43, armature 39 of relay 8, contact '70, conductor 71, brush 56, segment 59, conductor 60, winding of buzzer relay 61, conductor 64, conductor 72, ringer 19, line'wire erated to pull up its armature, will release its 1, lower outer spring contact 78 0f. key a, lower inner contact 45 to the positive terminal of Central office battery 3.

The bu'zzercircuit above referred to which is closed by operation of the buzzer relay 61 when the brush 56 is moved to segment 59 may be traced as follows: negative terminal of local bat tery 6, conductor 32, conductor 77, buzzer 20, conductor 78, armature of relay 61, contact '76, conductor '79, conductor 88 to the positive terminal of local battery 6.

the left-hand winding of differential relay 7 to suchan extent as to allow the pull of the'righthand winding and the pull of the retracting spring l3'to move the armature 11 over against contact 14 and will bring into operation relay 8 which Will pull up its armature 39 against contact 40 and close the circuit-over the conductors 43 and ,44 to the galvanometer 24 at the central ofiice. This operation of themicrophone 5 caused by vibrations set up by the'buzzer 20 will resultin a signal being displayed at the central oflice'in the samemanner as when the wall of the protected structure is set into vibration by a blow from a hammer or the like.

The operation of the buzzer 20 and the consequen't operation of the microphone 5 and the causing of the signal to be displayed at the central office will indicate to an operator at the central office 13 that the system is in operating condition. 7

To serve as signalingmeans to indicate to an operator at the central office certain conditions existing in the system, there is shown at the central ofii'ce B, in addition to the drop relay 23 and the' galvanom'eter 24, a lamp 29. The lamp 29 is controlled by relay 31 and is provided to indicate an open in the normal circuit. In

'series with the energizing coil'25 of the galvanoineter 2 1 are. relays 30 and 31.

Relay 30 controlsthe operation of the drop relay 23 which is an additional controlling means for the drop signal to the controlling of it'throug'h the gal vanometer 24. Relay 31 which is normally oparmature when there is an open in the normal circuit and bring into circuit connection the lamp 29; The circuit for lamp 29 may be traced as follows: negative terminal of grounded centralofilce battery 3, conductor 48, armatureof relay 31,.contact 52, conductor 53, lamp 29, conductor 54 to ground. I

-In order to provide adjustment facilities in regard to the condition of differential relay 7 which has in series with its left-hand winding the; lamp 9 and relay 10,"there is provided in series with the right-hand winding and the relay 15 an adjustable resistance 80 which merely for the purpose of illustration has been shown as comprising three sections, or three resistance coils connected in series; Each of these coils may be of a different value to the others. 7 These traced as follows: negative terminal of localv battery 6, conductor 32, conductor 82, movable contact 81, resistance element 80, or any portion thereof, conductor 83, armature 18 of relay 8, contact 84, winding of relay 15, right-hand windingof'differentia'l relay '7, contact 12, armature 1, conductor 36, conductor '79, conductor 88 to the positive terminal of local battery 6. By including in the circuit containing the righthand winding of differential relay 7 various portions of the adjustable resistance 80, the pull of the right-hand winding of differential relay 7 may be so adjusted with respect to the pull of the retracting spring 13 and the pull of the left-hand winding as to make the diiferential relay '7 very sensitive and this circuit maybe so adjusted that comparatively slight decreases in current caused by breathing of the microphone 5 Willnot cause the differential relay '7 to operate, but comparatively large changes in resistance occurring in the microphone caused by vibrations imparted to the wall structure to which the microphone is attached, will change the condition of relay 7' to such an extent that the pull of the left-hand winding which contains a greater number of turns thanthe right-hand winding will be overcome by the pull of the right-hand winding and the pull of the retract' ing spring 13.

The ringer 19'is not operated by current from the central office battery 3', but is only operated when the high potential batte'ry2'2 is brought into the circuit and indicates toan attendant at the protected premises that tests are being made from the central c'ffice of the condition of the system. I

It will be apparent that varicus modifications may be made in the system disclosed and described, such for instance as replacement of the lamp 9 by anysuitableresistance element, the resistance of which will increase with current and which will prevent comparatively small changes in resistance of the microphone 5 from affecting the diiferential relay 7, without departing from the spirit of the invention as set forth in the following claim.

1 What isclaimed is;

In a protective system for vaults and the like having a carbon granular transmitter button operated by vibrations imparted to the vault structure, an electrical circuit including said transmitter button, a,c ircuit closing relay con} trolled by operation of the said transmitter button and an alarm-controlled by said circuit closing relay, a resistance element connected be tween saidtransmitter button and said circuit closing relay, said resistance element having the characteristic of slowly increasing in res'istanceWith an increase current and slowly decreasing in resistance-with a decrease in current and preventing slow changes in the resistance of said transmitter button caused by breathing action of the carbon in said trans: mitter button from effecting operation of said circuit closing relay. r V

- JOSEPH C. FIELD. 

